Control system



H. H. GORREE May 28, 1940.

CONTROL S YSTEM Original Filed Feb. 25, 1935 INVENTOR.

HARVARD H. GORRIE Patented May 28, 1940 UNITED STATES CONTROL SYSTEMHarvard H. Gorrie, Cleveland Heights, Ohio, as-

- signor to Bailey ion of Delaware Meter Company, a corporariginalapplication February 25, 1935, Serial No. 8,047, now Patent No.2,098,914, dated November 9, 1937.

Divided and this application April 19, 1937, Serial No. 137,667

20 Claims.

This invention relates to control systems for establishing ormaintaining substantially constant any desired electrical, thermal,chemical, physical or other variable condition through the control of acorrective agent or agents. More particularly my invention relates tocontrol systems wherein a fluid pressure is utilized as the motive powerfor actuating devices to control the rate of application of correctiveagents.

It is an object of my invention to provide a control system wherein thecondition under control is rapidly restored to a predetermined value,upon deviation therefrom, without over-travel or hunting. I

A further object of my invention is to provide a control system whereinthe control of the pressure fluid by a device sensitive to thecontrolled condition may be readily transferred to manually-operateddevices without settingup disturbances in the system.

A further object is to provide a control system wherein individualunits, each contributing to the production of the controlled conditionmay be operated at different rates, one from another, and wherein thecontrol of the rate of supply of an agent, or agents, by the controlledcondition to each unit is modified to maintain such units at highestoperating efficiency.

The present application constitutes a division of my application, SerialNo. 8,047, filed February 25, 1935, in the United States Patent Oflice,now

Patent No. 2,098,914, granted November 9, 1937,

- and is directed particularly to the selector valve,

or mechanism, through whose agency an operator may manually control ormay selectively put the control on an automatic basis.

These and other objects will be apparent from the following descriptionand the drawing in which:

Fig. 1 is a diagrammatic representation of a control system embodying myinvention.

Fig. 2 is a schematic illustration partially in section of a selectorswitch utilized in myinvention.

Referring to Fig. l, I have therein shown my control system utilized tomaintain a predetermined temperature within a tank I, which is suppliedwith a heating agent such as steam through a conduit 2. For regulatingthe flow of steam to the tank a valve 3 is located in the conduit 2 andactuated by a pressure fluid motor 4. As shown the pressure fluid motor4 is effective for positioning a movable valve member 5 against theprogressively increasing resistance of a spring 6 as the pressure of thefluid supplied the motor 4 increases.

Within the tank I may be disposed the bulb 7 of a temperature sensitivedevice having a Bourdon tube 8 adapted to position a movable valvemember 9 of a pilot valve In to establish a fluid pressure in accordancewith the temperature within the tank I. This pressure is in turneffective through the agency of a standardizing or pressure balancingrelay H for establishing a loading pressure normally governing theactuation of the motor 4. The loading pressure is conducted through apipe l2 to a selector valve l3 wherein it is effective for establishinga control pressure transmitted through the pipe M to, the motor 4. Thearrangement is such that as the temperature within the tank i increases,the pressure transmitted to the standardizing device II through theagency of the pilot I is proportionately decreased, thereby effecting amovement of the valve member in a closing direction to decrease the rateof flow of steam to the tank I.

The selector valve I3 is provided with suitable manually-operated valvesand mechanisms whereby control of the motor 4 may readily be transferredfrom the loading pressure established by the standardizing relay ll to aloading pressure established by an operator or attendant.

The pilot valve I0 is more fully disclosed, and is claimed, in thepatent to Johnson, No. 2,054,464, granted September 15, 1936. It issuflicient for the present disclosure to say that a loading pressureis'established in the pipe NA in proportion to or in relation to thetemperature to which the Bourdon tube 8 is sensitive.

The relay mechanism II is more fully disclosed and is claimed in theparent application, Serial No. 8,047, new Patent No. 2,098,914, of whichthe present application is a division.

'Suflice it to say that a loading pressure is effective in the pipe l2leading to the selector switch l3 and from which latter a pipe i4 goesto the fluid pressure motor 4. The present application, being primarilyconcerned with the selector switch i3, is not particularly interested inthe origin or magnitude of the loading pressure existing in the pipe I2or that which may exist in the pipe l4. Except that insofar as thepressure which exists in the pipe M is concerned this is selectivelythat of the pipe l2 or as established manually through the agency. ofthe' and extending rearwardly therefrom is a cam shaft 45, to which is.secured a hand operable valve switch 46. Suitably arranged on the camshaft are cams 41, 48 and 49 for positioning the movable valves 50, 5|and 52 of valve bodies 53, 54 and 55 respectively. On the mounting plate44 may be inscribed suitable legends for indicating the existing statusof the control system and directions for transferring the control fromautomatic to hand, or vice versa. As shown, the valve switch 46 is inthe hand position, indicating that the valves 50, 5| and 52 arepositioned so that the controlling pressure transmitted to the valve 3may be varied manually entirely independent of the loading pressureproduced by the'standardizing relay l I; by angularly positioning a knob56. As indicated by the legend angular positioning of the knob 55 in aclockwise direction decreases the controlling pressure whereascounter-clockwise positioning increases the controlling pressure.

Manual positioning of the knob 56 serves to actuate a relay 58, which inmany aspects is similar to the standardizing or pressure-balancing relayll hereinbefore described. The knob 56 is secured to a shaft 51journaled in the mounting plate 44, and passes through the wall of therelay 58. The relay 58 is divided into two chambers 20A and 21A by adiaphragm 59. Positioned in the chamber 20A is a compression spring 39Aurging the diaphragm 59 in one direction. Likewise positioned in thechamber 20A is a tension spring 40A fastened to the diaphragm 59 and toa longitudinally .movable block MA, and urging the diaphragm- 59 in theopposite direction. The movable block MA is threaded to the shaft 51 andupon angular positioning of the shaft 51 is moved longitudinally in thechamber 20A, thus increasing or decreasing the tension of the spring40A. When the knob 56 is angularly positioned in a clockwise directionthe movable block 4IA is'moved to the right, as viewed in the drawing,thus increasing the tension of the spring 40A, and reducing the netforce of the springs 39A and 40A against the diaphragm 59.

Located in the chamber 21A is a fulcrumed beam 33A adapted to actuate apressure fluid inlet valve 30A when displaced from the neutral positionin a counter-clockwise direction, or to actuate a pressure fluid exhaustvalve 3iA when displaced from the neutral position in a clockwisedirection. Pressure fluid admitted to the chamber 21A is effective formaintaining the diaphragm 59 in a neutral position and is transmittedthrough the valve 55 to the pipe M for actuating the motor 4.

The movable valve member 59 controlling the ingress of fluid pressurefrom the pipe l2 to the chamber 20A is shown in the closed position,whereas the movable valve member 5|, permitting egress of the pressurefluid within the chamber 20A to the atmosphere, is open. Accordingly theforce urging the diaphragm 59 to the left, as viewed in Fig. 2, is thatproduced by the springs 39A and 40A. If for example it is desired toreduce the fluid pressure effective on the motor 4, the hand operableknob 56 is rotated in a clockwise direction, thus increasing the tensionof the spring 40A, but reducing the net force urging the diaphragm 59 tothe left. Accordingly the pressure necessary to produce an equal butopposite force to maintain the fulcrumed beam 33A in the neutralposition is reduced, and the fulcrum beam 33A is displaced clockwiseactuating the valve member 3IA allowing the pressure within the chamber21A to decrease until it is in proportion to the force produced by thesprings 39A, 40A.

Further displacement of the knob 56 effects a further decrease in fluidpressure necessary to maintain the diaphragm 59 in the neutral position,and the relay 58 provides a convenient manually-operable means forvarying the fluid pres sure effective upon the motor 4 through any rangedesired.

In order that the operator may be advised of the position of the valve 5at all times, a pressure gage 60 may be provided, which is connected tothe chamber 21A. As the valve 5 is positioned in accordance with thepressure fluid transmitted to the motor 4 from the chamber 21A anindication of such pressure is in reality an indication of the positionof valve 5, and the gage may if desired be graduated to indicate valveposition. Anoperator thus manually adjusting the control system iscontinuously and instantaneously advised of changes in the rate ofapplication of the corrective agent.

When it is desired to transfer the means regulating the rate ofapplication of the corrective agent from hand to automatic control, thetransfer switch 46 is rotated 90 in the direction indicated by the arrowto the reset position. Such rotation efiects an opening of the valve 53,and a closure of the valves 54 and 55. Pressure variations from thestandardizing relay- II are thus transmitted through the pipe I! to thechamber 20A and are effective upon the diaphragm 59. The magnitude ofthe pressure within the pipe I2 is indicated by a gage 6|. An operatormay then observe the difference between the loading pressure produced bythe standardizing relay II and that which will be made effective uponthe motor 4 by determining the difference between the readings of thegages 60 and iii. In order that the transfer from hand to automaticcontrol may be made as smoothly as possible without causing disturbancesin the system it is desirable that the difference in the loadingpressure transmitted through the pipe I2 and that which will be madeeffective upon the motor 4 through the pipe I4, be as small as possiblebefore the transfer is made. Thus with the transfer switch in the resetposition an operator is given an opportunity to deteremine thisdifference, and by proper manipulation of the knob 56 may make thepressures identical before making the transfer.

Further displacement of the transfer switch 46 from the reset positionto the automatic position permits the valve 53 to remain open, the valve54 to remain closed, but opens the valve 55, thus permitting pressureswithin the chamber 21A to be transmitted through the pipe l4 to themotor 4 and variations in loading pressure conducted through the pipe l2to the chamber 20A will thereafter produce corresponding variations inthe controlling pressure transmitted to the motor 4. If desired thecontrolling pressure transmitted to the motor 4, may be increased aboveor. decreased below the loading pressure established in the chamber 20Aby manual operation of the knob 56, which thus provides a means formodifying the control of the rate of application of the producing agentby the controlled condition to compensate or correct, for example, forvariations in the thermal content, chemical constituents, etc., of theproducing agent.

In transferring from automatic to hand control it is also desirable thatthe operation be accomplished without undue disturbance in the controlsystem or in the apparatus to which it is applied. To accomplish this areset position is provided as shown between the automatic andhandpositions. In this reset position valve 55 is closed, valve 54 isopened, allowing the pressure fiuid within the chamber 20A to exhaust;and valve 53 is closed. The knob 56 may then be manipulated until thecontrolling pressure is substantially the same as existed immediatelyprior to the transfer switch 46 being moved from the automatic positionto the reset position; and as the valve 55 is closed such a justment maybe made without disturbing the position of the valve 5. After thecontrolling fluid pressure has been brought to the desired value bymanipulation of the knob 56,-the transfer switch may beturned to the"hand position, with the assurance that the valve 5 will not bepositioned suddenly from its former position. 1

While in the foregoing description I have used specific apparatus toillustrate my invention, it is to be understood that I am not to belimited thereby, but 'that my invention is applicable to a wide varietyof applications.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is:

1. The method of transferring control of a.

pressure fluid actuated device from a first fluid pressure to a secondfluid pressure which comprises rendering said vdevice insensitive tochanges in the first fluid pressure, determining the magnitude of thefirst fluid pressure, making the second fluid pressure substantiallyequal to the first fluid pressure, and rendering the device sensitive tochanges in the second fluid pressure.

2. The method of transferring control of a device actuated by aregulating fluid pressure produced by a pressure relay normallysensitive to a controlling fluid pressure to manual control, whichcomprises, isolating the relay, determining the magnitude'of thecontrolling fluid pressure, adjusting the relay to produce a pressuresubstantially equal to the controlling fluid pressure, and rendering therelay accessible to the regulating fluid pressure.

3. In a fluid pressure actuated control system 'wherein a controllingfluid pressure produces a sure, and connecting the regulating chambertothe regulating pressure.

4. In a fluid pressure actuated control system wherein a controllingfluid pressure produces a regulating fluid pressure for actuating adevice through the agency of a relay having a controlling pressure fluidchamber and a regulating pressure fluid chamber, the method oftransferring from hand to automatic control which comprises,determiningthe magnitude of the regulating fluid pressure, disconnectingthe regulating chamber from the regulating fluid pressure and connectingthe controlling chamber to the controlling fluid pressure, adjusting therelay to produce a pressure in the regulating chamber substantiallyequal to the determined magnitude of the regulating fluid pressure, andconnecting the regulating chamber to the regulating pressure.

5. A selector valve for a fluid pressure operated control system,comprising in combination, separate pressure lines, a pressure relay fortransmitting pressure variations from one of said pressure lines to theother of said pressure lines, valve means positioned in each of saidlines for controlling the transmittal of pressure, and means forprogressively operating said valves in a predetermined cycle;

6. A selector valve comprising in combination, a'pressure relay, a pipefor conducting a controlling fluid pressure to said relay, a pipe fortransmitting the controlled fluid pressure from said relay, handoperable means for modifying the control of said controlled fluidpressure by said controlling fluid pressure, valve means for controllingthe transmittal of the con-trolling fluid pressure to said relay, valvemeans for controlling the transmittal of the controlled fluid pressurefrom said relay, a relief valve positioned between said first namedvalve and said relay, and hand operable means for progressivelyoperating said valves in unison through a predetermined cycle.

'7. A selector valve comprising in combination, a pressure relay, afirst pipe for conducting a controlling fluid pressure to said relay, afirst valve for controlling the transmittal of the controlling fluidpressure to said relay, a first pressure gage for indicating themagnitude of the controlling fluid pressure connected to said first pipeahead of-said first valve, a-second pipe for conducting the controlledfluid pressure from said relay, a second valve for controlling thetransmittal of the controlled fluid pressure from said relay, a secondpressure gage for indicating the magnitude of the controlled fluidpressure connected to said second pipe between said relay and saidsecond valve, and hand operable means for progressively operating saidvalves in unison through a predetermined cycle.

8. A selector valve comprising in combination, a pressure relay, a firstpipe for conducting a pressure gage for indicating the magnitude of thecontrolling fluid pressure connected to said first pipe ahead of saidfirst valve, a relief valve positioned between said first valve and saidrelay, a second pipe for conducting the controlled fluid pressure fromsaid relay, a second valve for controlling the transmittal of thecontrolled fluid pressure from said relay, a second pressure gage forindicating the magnitude of the controlled fluid pressure connected tosaid second pipe between said relay and said second valve, manuallyoperablemeans movable to a plurality of successive positions foroperating said valves in unison through a predetermined cyclic program,said manually operable means in one position maintaining said first andsecond valves open and said relief valve closed whereby variations inthe controlling fluid pressure effect corresponding variations in thecontrolled fluid pressure, when moved to a second positionsimultaneously closing said first and second valves and opening saidrelief valve, when moved to a third position opening said second valvewhile maine taining said relief valve and said first valve open, andwhen moved to a fourth position simultaneously closing said secondvalve. and said relief valve and opening said first valve; and manually9. A selector valve comprising in combination, a pressure relay, a pipefor conducting a controlling fluid pressure to said relay, a pipe fortransmitting the controlled fluid pressure from said relay, handoperable means for modifying the control of said controlled fluidpressure by said controlling fluid pressure, valve means for controllingthe transmittal of the controlling fluid pressure to said relay, valvemeans for controlling the transmittal of the controlled fluid pressurefrom said relay, and hand operable means for progressively operatingsaid valves in unison through a predetermined cycle.

10. A selector valve comprising in combination, a pressure relay, a pipefor conducting a controlling fluid pressure to said relay, a pipe fortransmitting the controlled fluid pressure from said relay, valve meansfor controlling the transmittal of the controlling fluid pressure tosaid relay, valve means for controlling the transmittal of thecontrolled fluid pressure from said relay, and hand operable means for,progressively operating said valves in unison through a predeterminedcycle.

11. A selector valve for a fluid pressure operated control systemcomprising in combination, separate pressure lines, a pressure relay fortransmitting pressure variations from one of said pressure lines to theother of said pressure lines, valve means positioned in each of saidlines for controlling the transmittal of pressure, a cam shaft, aplurality of cams mounted on said shaft, each of said cams adapted toactuate one of said valve means, and hand operable means for angularlypositioning said cam shaft whereby said valves are progressivelyoperated in unison through a predetermined cycle.

12. A selector valve comprising in combination, a pressure relay, a pipefor conducting a controlling fluid pressure to said relay, a pipe fortransmitting the controlled fluid pressure from said relay, handoperable loading means for varying the magnitude of the controlled fluidpressure for a given magnitude of the controlling fluid pressure, valvemeans for controlling the transmittal of the controlling fluid pressureto said relay, and hand operable means for opening and closing saidvalve means whereby when said valve means is in closed positionvariations in the controlled fluid pressure being produced solely bysaid hand operable loading means, and when said valve means is in openposition variations in the controlled fluid pressure being produced bysaid hand operable means and said controlling fluid pressure.

13. A selector valve comprising in combination, a pressure relay, a pipefor conducting a controlling fluid pressure to said relay, a pipe fortransmitting the controlled fluid pressure from said relay, handoperable loading means for varying the magnitude of the controlled fluidpressure for a given magnitude of the controlling fluid pressure, afirst valve for controlling the transmittal of the controlling fluidpressure to said relay, a relief valve positioned between said firstnamed valve and said relay, means for closing said first valve andsimultaneously opening said relief valve whereby said hand operableloading means solely controls the magnitude 0 of the controlled fluidpressure.

14. The method of transferring control of a pressure fluid actuateddevice from a first fluid pressure to a second fluid pressure whichcomprises rendering said device insensitive to changes in the flrstfluid pressure, making the second fluid pressure substantially equal tothe first fluid pressure impressed on said device, and rendering thedevice sensitive to changes in the second fluid pressure.

15. The method of transferring control of a device actuated by aregulating fluid pressure produced by a pressure relay normallysensitive to a controlling fluid pressure to manual control, whichcomprises, isolating the relay, adjusting the relay to produce apressure substantially equal to the regulating fluid pressure, andrendering the relay accessible to the regulating fluid pressure.

16. A selector valve for transferring control of a pressure fluidactuated device from a first-fluid pressure to a second fluid pressurecomprising a manually operable valve means for selectively renderingsaid device sensitive to changes in said first fluid pressure, manuallyoperable means for establishing said second fluid pressure, and manuallyoperable valve means for selectively rendering said device sensitive tosaid second fluid pressure.

17. A selector valve for transferring control of a pressure fluidactuated device from a first fluid pressure to a second fluid pressurecomprising in combination, 'valve means for rendering said deviceselectively insensitive or sensitive to changes in said first fluidpressure, manually operable means for establishing said second fluidpressure, valve means for selectively rendering said device insensitiveor sensitive to said second fluid pressure, and hand operable means forprogressively operating said valves in unison through a predeterminedcycle.

18. Control apparatus for effecting control of a variable by fluidpressure transmission and arranged for alternative automatic or manualcontrol, comprising means to adjust the fluid pressure established bythe control to which change is to be made as to cause the said controlto produce a pressure substantially equal to that produced by thecontrol from which change is to be made.

19. In control apparatus effecting control of a device by fluid pressuretransmission, a selector valve providing for selective control of thefluid pressure by. manual or automatic means, said selector valvecomprising means to adjust the fluid pressure established by the controlto which change is to be made so that the fluid pressure establishedthereby is substantially equal to that produced by the control fromwhich change is to be made.

20. In control apparatus effecting control of a device by fluid pressuretransmission, a selector valve providing for selective control of thefluid pressure by manual or automatic means, said selector valvecomprising means to prevent changes in said fluid pressure by eithersaid automatic or manual means, and means to adjust the fluid pressureestablished by the control to which change is to be made so that thefluid pressure established thereby is substantially equal to thatproduced by the control from which change is to be made.

HARVARD H. GORRIE.

